CN208369202U - A kind of current foldback circuit of Switching Power Supply - Google Patents
A kind of current foldback circuit of Switching Power Supply Download PDFInfo
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- CN208369202U CN208369202U CN201820938245.2U CN201820938245U CN208369202U CN 208369202 U CN208369202 U CN 208369202U CN 201820938245 U CN201820938245 U CN 201820938245U CN 208369202 U CN208369202 U CN 208369202U
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Abstract
The utility model discloses a kind of current foldback circuits of Switching Power Supply, comprising: external power supply, control signal end, first resistor and door, the first triode, the 4th resistance, comparator, second resistance, optical coupling isolator, the 5th resistance, the 6th resistance, the 7th resistance, the second triode, third transistor, the 8th resistance, the 4th triode, the 5th triode, IGBT switching tube, the 9th resistance, twelfth resistor, the tenth resistance and diode；By the current foldback circuit, IGBT is turned off in time in the case where circuit overcurrent, be ensure that the safety of circuit work, is avoided the damage of Switching Power Supply, save the effect of maintenance and replacement；Optical coupling isolator is used simultaneously, is reached good electrical isolation effect, is improved the stability of circuit；Emitter follower is formed by triode both ends parallel resistance, reduces shutdown and the service time of triode；The circuit structure is simple, and stability is high, and high safety is quick on the draw.
Description
Technical field
The utility model belongs to switch power technology field, and in particular to a kind of current foldback circuit of Switching Power Supply.
Background technique
ICBT had not only had the high-speed switch and voltage drive characteristics of power MOSFET, but also with huge transistor (GTR)
Low saturation voltage characteristic and the ability for easily realizing larger current, are widely used in the fields such as electric machine speed regulation, UPS and Switching Power Supply；
In the IGBT application of Switching Power Supply, overcurrent protection is a key technology therein, and current foldback circuit is not only related to
The working performance and operational safety of IGBT itself also influences the performance and safety of whole system；It therefore, is guarantee Switching Power Supply
Safety, design a kind of current foldback circuit for Switching Power Supply be very it is necessary to.
Utility model content
To overcome technological deficiency of the existing technology, the utility model discloses a kind of overcurrent protection of Switching Power Supply electricity
Road ensure that the stability and safety of Switching Power Supply work.
Technical solution adopted by the utility model to solve its technical problems is a kind of current foldback circuit of Switching Power Supply,
It include: external power supply, control signal end, first resistor and door, the first triode, the 4th resistance, comparator, second resistance, light
Coupling isolator, the 5th resistance, the 6th resistance, the 7th resistance, the second triode, third transistor, the 8th resistance, the four or three pole
Pipe, the 5th triode, IGBT switching tube, the 9th resistance, twelfth resistor, the tenth resistance and diode；The external power supply is logical
Cross first resistor connection and the first input end of door, connect with the second input terminal of door outside control signal end, the with door
One input terminal is also connected with the collector of the first triode, and the emitter of the first triode passes through the 4th resistance eutral grounding, the one or three pole
The output end of the base stage connection comparator of pipe, the power end of comparator connect external power supply, and the ground terminal ground connection of comparator is compared
The non-inverting input terminal of device connects external power supply by the 8th resistance, and the 7th resistance and the are connected in series between external power supply and ground
The inverting input terminal of the common end connection comparator of six resistance, the 7th resistance and the 6th resistance, passes through second with the output end of door
Resistance connects the input terminal of optical coupling isolator, the base of output end connection the second triode and third transistor of optical coupling isolator
Pole, the collector of the triode in optical coupling isolator also pass through the 5th resistance connection external power supply, the second triode and the three or three
The base stage of pole pipe is also connected with the common end of the 6th resistance and the 7th resistance, the emitter ground connection of the second triode, the second triode
Collector connection comparator non-inverting input terminal, the collector of the second triode is also connected with the first end of the tenth resistance, the tenth
The anode of the second end connection diode of resistance, the collector of the cathode connection IGBT switching tube of diode, third transistor
The collector of emitter ground connection, third transistor connects the base stage of the 4th triode and the base stage of the 5th triode, external power supply
Also it is connected in series with twelfth resistor and the 9th resistance between ground, the base stage of the base stage of the 4th triode and the 5th triode is also
It is connected with the common end of twelfth resistor and the 9th resistance, the collector of the 4th triode connects external power supply, the 4th triode
Emitter connect the emitter of the 5th triode, the grounded collector of the 5th triode, the emitter of the 4th triode and the
The grid of the emitter connection IGBT switching tube of five triodes, the emitter ground connection of IGBT switching tube, the current collection of IGBT switching tube
Pole connects external power supply.
Preferably, 3rd resistor is also connected between the base stage of first triode and the output end of comparator.
Preferably, the chip model that the comparator uses is LM193.
Preferably, the grid of the emitter of the emitter of the 4th triode and the 5th triode and IGBT switching tube it
Between be also connected with eleventh resistor.
Preferably, first is also connected between the emitter of the 4th triode and the emitter and ground of the 5th triode
Voltage-stabiliser tube and the second voltage-stabiliser tube, the emitter of the 4th triode and the emitter of the 5th triode connect the sun of the first voltage-stabiliser tube
Pole, the cathode of the first voltage-stabiliser tube connect the cathode of the second voltage-stabiliser tube, the plus earth of the second voltage-stabiliser tube.
Preferably, the chip model used with door is CD4081.
The beneficial effects of the utility model are: being turned off in time in the case where circuit overcurrent by the current foldback circuit
IGBT ensure that the safety of circuit work, avoid the damage of Switching Power Supply, save the effect of maintenance and replacement；It adopts simultaneously
With optical coupling isolator, reaches good electrical isolation effect, improve the stability of circuit；Pass through triode both ends parallel resistance group
At emitter follower, shutdown and the service time of triode are reduced；The circuit structure is simple, and stability is high, high safety, instead
It answers sensitive.
Detailed description of the invention
Fig. 1 is a kind of circuit diagram of the current foldback circuit of Switching Power Supply of the utility model.
Appended drawing reference: VCC- external power supply, A- control signal end, R1- first resistor, Y- and door, the first triode of T1-,
The 4th resistance of R4-, R3- 3rd resistor, U- comparator, R2- second resistance, OC- optical coupling isolator, the 5th resistance of R5-, R6-
Six resistance, the 7th resistance of R7-, the second triode of T2-, T3- third transistor, the 8th resistance of R8-, the 9th resistance of R9-, T4-
Four triodes, the 5th triode of T5-, the tenth resistance of R10-, D1- diode, R11- eleventh resistor, the first voltage-stabiliser tube of D2-,
The second voltage-stabiliser tube of D3-, IGBT-IGBT switching tube, R12- twelfth resistor.
Specific embodiment
More detailed description is done to the embodiments of the present invention below in conjunction with attached drawing and appended drawing reference, makes to be familiar with ability
The technology people in domain can implement accordingly after studying this specification carefully.It should be appreciated that specific embodiment described herein is only to solve
The utility model is released, is not used to limit the utility model.
A kind of current foldback circuit of Switching Power Supply, comprising: external power supply VCC, control signal end A, first resistor R1, with
Door Y, the first triode T1, the 4th resistance R4, comparator U, second resistance R2, optical coupling isolator OC, the 5th resistance R5, the 6th electricity
Hinder R6, the 7th resistance R7, the second triode T2, third transistor T3, the 8th resistance R8, the 4th triode T4, the 5th triode
T5, IGBT switching tube IGBT, the 9th resistance R9, twelfth resistor R12, the tenth resistance R10 and diode D1；The external power supply
VCC passes through the first input end of first resistor R1 connection and door Y, and external control signal end is connect with the second input terminal of door Y
A, the collector of the first triode T1 is also connected with the first input end of door Y, and the emitter of the first triode T1 passes through the 4th electricity
R4 ground connection, the output end of the base stage connection comparator U of the first triode T1 are hindered, the power end of comparator U connects external power supply
The ground terminal of VCC, comparator U is grounded, and the non-inverting input terminal of comparator U is external by the 8th resistance R8 connection external power supply VCC
The public of the 7th resistance R7 and the 6th resistance R6, the 7th resistance R7 and the 6th resistance R6 is connected in series between power supply VCC and ground
The inverting input terminal of end connection comparator U, the input of optical coupling isolator OC is connect with the output end of door Y by second resistance R2
It holds, the base stage of the second triode T2 and third transistor T3 of output end connection of optical coupling isolator OC, in optical coupling isolator OC
The collector of triode also passes through the 5th resistance R5 connection external power supply VCC, the base of the second triode T2 and third transistor T3
Pole is also connected with the common end of the 6th resistance R6 and the 7th resistance R7, the emitter ground connection of the second triode T2, the second triode T2
Collector connection comparator U non-inverting input terminal, the collector of the second triode T2 is also connected with the first of the tenth resistance R10
End, the anode of the second end connection diode D1 of the tenth resistance R10, the collection of the cathode connection IGBT switching tube IGBT of diode D1
Electrode, the emitter ground connection of third transistor T3, the collector of third transistor T3 connect the base stage and the of the 4th triode T4
The base stage of five triode T5 is also connected in series with twelfth resistor R12 and the 9th resistance R9 between external power supply VCC and ground, the
The base stage of four triode T4 and the base stage of the 5th triode T5 are also connected with the public of twelfth resistor R12 and the 9th resistance R9
End, the collector of the 4th triode T4 connect external power supply VCC, and the emitter of the 4th triode T4 connects the 5th triode T5's
Emitter, the grounded collector of the 5th triode T5, the emitter of the 4th triode T4 and the emitter of the 5th triode T5 connect
Connect the grid of IGBT switching tube IGBT, the emitter ground connection of IGBT switching tube IGBT, the collector connection of IGBT switching tube IGBT
External power supply VCC；Specifically, the principle of the current foldback circuit are as follows: when circuit works normally；
When control signal end A input high level signal, high level signal is exported with door Y, optical coupling isolator OC is connected at this time,
Since the conducting of optical coupling isolator OC is grounded, the base voltage of the second triode T2 and third transistor T3 has been dragged down, this
When the second triode T2 and third transistor T3 base stage receive low level signal, the second triode T2 and third transistor T3 are
NPN type triode, NPN type triode receive low level cut-off, at this time the electricity of the 4th triode T4 and the 5th triode T5 base stage
Pressure is the voltage after the 9th resistance R9 and twelfth resistor R12 partial pressure, is high voltage, i.e. generation high level signal, the four or three pole
Pipe T4 is NPN type triode, and the 5th triode T5 is PNP type triode, therefore the 4th triode T4 receives high level signal and leads
Logical, the 5th triode T5 receives high level signal cut-off, and the grid of IGBT switching tube IGBT connects external power supply VCC at this time,
IGBT switching tube IGBT conducting；
When control signal end A input low level signal, low level signal is exported with door Y, optical coupling isolator OC ends at this time,
Due to the cut-off of optical coupling isolator OC, the base stage of the second triode T2 and the base stage of third transistor T3 receive the 7th resistance at this time
Voltage after R7 and the 6th resistance R6 partial pressure, is high voltage, i.e., generates high level signal, the second triode T2 and the three or three at this time
Pole pipe T3 receives high level signal conducting, since the conducting of third transistor T3 is grounded, the 4th triode T4 and the five or three at this time
The base voltage of pole pipe T5 is pulled low, the 4th triode T4 cut-off, the 5th triode T5 conducting, due to leading for the 5th triode T5
Ground is connected, the grid voltage ground connection of IGBT switching tube IGBT is pulled low at this time, IGBT switching tube IGBT cut-off；
When circuit generates over-current phenomenon avoidance, the bridge up and down of IGBT switching tube IGBT is straight-through, generates on IGBT switching tube IGBT
Very big electric current, the second triode T2 ends at this time, the voltage of the non-inverting input terminal of comparator U by IGBT switching tube IGBT collection
The voltage of electrode and emitter, diode D1, the tenth resistance R10 and the 8th resistance R8 partial pressure after voltage determine,
When circuit works normally, the non-inverting input terminal of IGBT switching tube IGBT conducting, comparator U receives low-voltage, than
The voltage of inverting input terminal input compared with device U is the voltage after the 7th resistance R7 and the 6th resistance R6 partial pressure, at this time comparator U
The voltage of non-inverting input terminal is less than the voltage of inverting input terminal, and comparator U exports low level signal, and the first triode T1 is NPN
Type triode, the first triode T1 receive low level signal cut-off, are only determined at this time by input end signal with the level of door Y output end
It is fixed；
When over-current phenomenon avoidance occurs, saturated phenomenon is moved back in the collector generation of IGBT switching tube IGBT, and comparator U's is same at this time
Phase input terminal current potential increases, and when the voltage of the inverting input terminal of comparator U is less than the voltage of non-inverting input terminal, comparator U is defeated
High level signal out, the first triode T1 receives high level signal conducting at this time, since the conducting of the first triode T1 is grounded, because
The voltage of this and the first input end of door Y is pulled low, and the first input end input low level signal with door Y controls signal at this time
A either high level signal or low level signal are held, is low level signal with door Y output end, at this time IGBT switching tube
IGBT cut-off, it is in an off state, to achieve the purpose that overcurrent protection；
Wherein the 9th resistance of the both ends third transistor T3 parallel connection also constitutes emitter follower, which provides
One quick current source, reduce third transistor T3 turns on and off the time.
3rd resistor R3 is also connected between the base stage of the first triode T1 and the output end of comparator U；Described
Three resistance R3 are current-limiting resistance, prevent the base current of the first triode T1 excessive and damage the first triode T1, improve circuit
Stability.
The chip model that the comparator U is used is LM193；LM193 has the advantages of low-power consumption, high sensitivity.
The grid of the emitter of the 4th triode T4 and the emitter of the 5th triode T5 and IGBT switching tube IGBT
Between be also connected with eleventh resistor R11；The eleventh resistor R11 lets out the grid stored charge of IGBT switching tube IGBT
It puts, prevents the charge accumulated of IGBT switching tube IGBT grid.
It is steady that first is also connected between the emitter of the 4th triode T4 and the emitter and ground of the 5th triode T5
The emitter of the emitter and the 5th triode T5 of pressure pipe D2 and the second voltage-stabiliser tube D3, the 4th triode T4 connects the first voltage-stabiliser tube
The anode of D2, the cathode of the first voltage-stabiliser tube D2 connect the cathode of the second voltage-stabiliser tube D3, the plus earth of the second voltage-stabiliser tube D3；It is described
First voltage-stabiliser tube D2 and the second voltage-stabiliser tube D3 prevents the grid of IGBT switching tube IGBT and the due to voltage spikes damage IGBT of emitter
Switching tube IGBT, shields.
The chip model used with door Y is CD4081；CD4081 is 42 inputs and door, the encapsulation of 14 foot of biserial, gold
Category-Oxidc-Semiconductor type complementation MOS.
The above content is the further descriptions made in conjunction with specific preferred embodiment to the utility model, cannot recognize
Determine specific embodiment of the present utility model to be only limited to these instructions.For the common skill of the utility model technical field
For art personnel, the other embodiments obtained in the case where not departing from the technical solution of the utility model be should be included in practical
In novel protection scope.
Claims (6)
1. a kind of current foldback circuit of Switching Power Supply, it is characterised in that: include: external power supply (VCC), control signal end (A),
First resistor (R1) and door (Y), the first triode (T1), the 4th resistance (R4), comparator (U), second resistance (R2), optocoupler
Isolator (OC), the 5th resistance (R5), the 6th resistance (R6), the 7th resistance (R7), the second triode (T2), third transistor
(T3), the 8th resistance (R8), the 4th triode (T4), the 5th triode (T5), IGBT switching tube (IGBT), the 9th resistance
(R9), twelfth resistor (R12), the tenth resistance (R10) and diode (D1)；The external power supply (VCC) passes through first resistor
(R1) first input end with door (Y) is connected, external control signal end (A) is connect with the second input terminal of door (Y), with door
(Y) first input end is also connected with the collector of the first triode (T1), and the emitter of the first triode (T1) passes through the 4th electricity
(R4) ground connection is hindered, the power end connection of the output end of base stage connection comparator (U) of the first triode (T1), comparator (U) is outer
It connects power supply (VCC), the non-inverting input terminal of the ground terminal ground connection of comparator (U), comparator (U) is outer by the connection of the 8th resistance (R8)
It connects power supply (VCC), the 7th resistance (R7) and the 6th resistance (R6), the 7th electricity is connected in series between external power supply (VCC) and ground
Resistance (R7) connects the inverting input terminal of comparator (U) with the common end of the 6th resistance (R6), passes through second with the output end of door (Y)
Resistance (R2) connect optical coupling isolator (OC) input terminal, optical coupling isolator (OC) output end connection the second triode (T2) and
The base stage of third transistor (T3), it is outer that the collector of the triode in optical coupling isolator (OC) also passes through the connection of the 5th resistance (R5)
It connects power supply (VCC), the base stage of the second triode (T2) and third transistor (T3) is also connected with the 6th resistance (R6) and the 7th resistance
(R7) common end, the emitter ground connection of the second triode (T2), collector connection comparator (U) of the second triode (T2)
Non-inverting input terminal, the collector of the second triode (T2) are also connected with the first end of the tenth resistance (R10), the tenth resistance (R10)
Second end connects the anode of diode (D1), the collector of cathode connection IGBT switching tube (IGBT) of diode (D1), third
The emitter of triode (T3) is grounded, and the collector of third transistor (T3) connects the base stage and the five or three of the 4th triode (T4)
The base stage of pole pipe (T5) is also connected in series with twelfth resistor (R12) and the 9th resistance between external power supply (VCC) and ground
(R9), the base stage of the 4th triode (T4) and the base stage of the 5th triode (T5) are also connected with twelfth resistor (R12) and the 9th
The collector of the common end of resistance (R9), the 4th triode (T4) connects external power supply (VCC), the transmitting of the 4th triode (T4)
Pole connects the emitter of the 5th triode (T5), the grounded collector of the 5th triode (T5), the transmitting of the 4th triode (T4)
Pole connects the grid of IGBT switching tube (IGBT), the emitter of IGBT switching tube (IGBT) with the emitter of the 5th triode (T5)
The collector of ground connection, IGBT switching tube (IGBT) connects external power supply (VCC).
2. a kind of current foldback circuit of Switching Power Supply as described in claim 1, it is characterised in that: first triode
(T1) 3rd resistor (R3) is also connected between the output end of base stage and comparator (U).
3. a kind of current foldback circuit of Switching Power Supply as described in claim 1, it is characterised in that: the comparator (U) is adopted
Chip model is LM193.
4. a kind of current foldback circuit of Switching Power Supply as described in claim 1, it is characterised in that: the 4th triode
(T4) the tenth is also connected between the emitter of emitter and the 5th triode (T5) and the grid of IGBT switching tube (IGBT)
One resistance (R11).
5. a kind of current foldback circuit of Switching Power Supply as claimed in claim 4, it is characterised in that: the 4th triode
(T4) the first voltage-stabiliser tube (D2) and the second pressure stabilizing are also connected between the emitter and ground of emitter and the 5th triode (T5)
It manages (D3), the sun of the emitter connection the first voltage-stabiliser tube (D2) of the emitter and the 5th triode (T5) of the 4th triode (T4)
Pole, the cathode of the cathode connection the second voltage-stabiliser tube (D3) of the first voltage-stabiliser tube (D2), the plus earth of the second voltage-stabiliser tube (D3).
6. a kind of current foldback circuit of Switching Power Supply as described in claim 1, it is characterised in that: described to be used with door (Y)
Chip model be CD4081.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820938245.2U CN208369202U (en) | 2018-06-19 | 2018-06-19 | A kind of current foldback circuit of Switching Power Supply |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820938245.2U CN208369202U (en) | 2018-06-19 | 2018-06-19 | A kind of current foldback circuit of Switching Power Supply |
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| CN208369202U true CN208369202U (en) | 2019-01-11 |
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| CN201820938245.2U Active CN208369202U (en) | 2018-06-19 | 2018-06-19 | A kind of current foldback circuit of Switching Power Supply |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109757020A (en) * | 2019-03-12 | 2019-05-14 | 江苏北方湖光光电有限公司 | A kind of control circuit based on low-light protection |
| CN110830016A (en) * | 2019-12-16 | 2020-02-21 | 天津瑞源电气有限公司 | IGBT short-circuit protection circuit |
| CN112098739A (en) * | 2020-05-27 | 2020-12-18 | 深圳天邦达科技有限公司 | Battery package short-circuit protection test circuit, circuit board and test equipment |
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2018
- 2018-06-19 CN CN201820938245.2U patent/CN208369202U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109757020A (en) * | 2019-03-12 | 2019-05-14 | 江苏北方湖光光电有限公司 | A kind of control circuit based on low-light protection |
| CN109757020B (en) * | 2019-03-12 | 2023-08-15 | 江苏北方湖光光电有限公司 | Control circuit based on shimmer protection |
| CN110830016A (en) * | 2019-12-16 | 2020-02-21 | 天津瑞源电气有限公司 | IGBT short-circuit protection circuit |
| CN112098739A (en) * | 2020-05-27 | 2020-12-18 | 深圳天邦达科技有限公司 | Battery package short-circuit protection test circuit, circuit board and test equipment |
| CN112098739B (en) * | 2020-05-27 | 2024-02-23 | 深圳天邦达科技有限公司 | Battery pack short-circuit protection test circuit, circuit board and test equipment |
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